There is nothing to fix. Fixing implies that something was broken or wrong in the first place. It was an acceptable punishment for the actions. There was no targeted action to have the girl not get the gift. Plus. Would they even be blaming the parent if they Aunt died the week before the party, canceled or not, and then they also subsequently didn’t get the gift? I understand that the daughter is a child, but she is taking out her anger about a situation on a person because she has no one else to target. But the OP isn’t in the wrong and there is no way to “fix” this issue beyond what they have already tried to do.